Random power gate



Feb. 10, 1970 LINE D. G- GRESHAM RANDOM POWER GATE Filed Jan. 7, 1966 INVENTOR.

United States Patent US. Cl. 315-200 Claims ABSTRACT OF THE DISCLOSURE Arandom-gated power controller for generating a flickering action in anelectric lamp simulating candlelight. The controller consists of a pairof freely swingable conductive massive bodies, one of them magnetic,suspended adjacent and offset from an electromagnet. When theelectromagnet is energized, it drives the magnetic conductive body intostriking contact with the other conductive body, causing mutual rebound.The bodies are connected so as to shunt the electromagnet when theyengage each other. The bodies also shunt a resistor in series with thelamp, causing corresponding variations in the current supplied to thelamp. The bodies swing in orbital paths relative to the electromagnet.

This invention relates to electrical power-gating devices, and moreparticularly to a device for providing randomgating action to anelectrical load, for example, to an incandescent electric light bulb toprovide a flickering action intended to simulate the flickering actionof an open flame such as that which is obtained from a candle.

A main object of the invention is to provide a novel and improvedgated-power controller possessing electrical characteristics which aretruly random in all three parameters of amplitude, frequency and phase,and which is particularly suitable for random modulation of apredetermined portion of the power connected to an incandescent lamp,whereby the resulting power fluctuations produce an unsteady falteringlight output from the lamp, creating the illustion of open flame, therandom-gating device being applicable for use with appropriate lightingfixtures, such as candelabras, outdoor post lanterns, wallmounted coachlamps, and similar decorative sources of illumination, the resultobtained by the use of the random power-gating device enhancing, to avery significant degree, the decorative effects provided by theassociated fixtures.

A further object of the invention is to provide an improved randompower-gating device which is especially useful in conjunction withlight-producing loads, such as incandescent electric lamps to produce aflickering or unsteady light output, creating the illusion of openflame, and which is also useful, when connected to capacitive orconductive loads or in combinations thereof, to generate broad-bandradio-frequency energies having random, nonrepetitive characteristics,namely, for generating white noise.

A still further object of the invention is to provide an improved randompower-gating device which is relatively simple in construction, which iscompact in size, which employs relatively inexpensive components, whichis durable in construction, which is capable of operating lamp loadsover a very wide range, which requires no adjustments throughout itslife, and which is operable over wide ambient temperature ranges so thatit can be used out-ofdoors under the most severe weather extremes withpractically no perceptible change in its operational characteristics.

A still further object of the invention is to provide an improved randompower-gating device which is reliable in operation, which is relativelyinsensitive to ordinary ambient conditions of vibration and shock, whichprovides consistent reliable operation over long periods of time, whichprovides a truly random power supply to its load, whereby the outputthereof is truly random in form, containing a relatively gentle flickerrather than a relatively continuous sputtering effect, and whichproduces relatively negligible radio-frequency interference.

A still further object of the invention is to provide an improved randompower-gating device for use in modulating the power supply to alight-producing source, such as an incandescent lamp, to cause thesource to generate a flickering or wavering light output simulating thatprovided by an open flame, the power-gating device maintaining a highlevel of light output while, at the same time, providing the desiredflame-simulation, as well as sufficiently limiting the range of powerfluctuations and the rate of such power fluctuations so as not to causedeterioration or reduction in life of the lamps with which it isemployed.

Further objects and advantages of the invention will become apparentfrom the following description and claims, and from the accompanyingdrawing, wherein:

FIGURE 1 is a top plan view of an improved random power-gating deviceconstructed in accordance with the present invention.

FIGURE 2 is a front elevational view of the powergating device shown inFIGURE 1'.

FIGURE 3 is a side elevational view of the powergating device of FIGURESl and 2.

FIGURE 4 is a rear elevational view of the powergating device of FIGURES1, 2 and 3.

FIGURE 5 is a wiring diagram schematically illustrating the electricalconnections of the various components of the random power-gating deviceof FIGURES 1 to 4.

FIGURE 6 is a partial circuit diagram showing a modification of thepresent invention.

Referring to the drawing, 11 generally designates an improved randompower-gating device constructed in accordance with the presentinvention. The device 11 comprises a generally rectangular mainsupporting plate 12 of insulating material formed with a largerectangular notch 13 opening at its bottom end. Secured to the plate 12are a plurality of metal terminals 14 to 18 which are employed asterminal connections for the respective electrical components of theapparatus. A pair of additional terminal members 19 and 20 are securedto plate 12 above the notch 13, the terminals 19 and 20 being spacedhorizontally and being employed both as supports for certain mechanicalcomponents of the apparatus, and also as electrical terminals, as willbe presently described.

Secured in the bottom of notch 13, namely, secured in the open bottomendof said notch, is a vertically-arranged electromagnet 21 provided atits top end with the exposed pole piece 22. Transversely-secured overthe top portion of the notch 13 is a horizontal bar member 23 ofsuitable insulating material formed with spaced outwardly-projectingguide ring elements 24 and 25 located below and substantially invertical registry with the terminal members 19 and 20. A spherical ball26 of ferrous magnetic material is suspended resiliently from theterminal member 19. Thus, the ball 26 is provided with theupwardly-extending supporting rod 27. A coiled spring 28 connects thetop end of rod 27 to the terminal member 19. Thus, the ferrous sphere 26of magnetic material is suspended from the terminal element 19 andnormally is located in a position above and adjacent to the pole piece22, but displaced laterally a short distance from the vertical centerline of the pole piece namely, spaced laterally to the left of the polepiece vertical center line as viewed in FIGURE 2.

Similarly mounted over the pole piece 22, but spaced to the right of thevertical center line of the pole piece 22 is a vertically-arrangedcylindrical block 29 of nonnagnetic metal, the block 29 being providedwith the ipwardly-extending, axially-connected supporting rod 30 vhosetop end is connected by a coiled spring 31 to the erminal member 20. Thevertical cylindrical block 29 s thus supported adjacent to the sphere 26over the pole JlCC 22, being located in the path of oscillation of the;phere 26 and thus being subject to impact by said :phere. Conversely,the sphere 26 is subject to impact by he non-magnetic metal block 29when said metal block )scillates.

The rod element 27 and the spring 28 are electrically- :onductive, andsimilarly, the rod element 30 and the :pring 31 areelectrically-conductive, so that the spherical nember 26 iselectrically-connected to the terminal 19 md the cylindrical block 29 iselectrically-connected to he terminal 20. The springs 28 and 31 bias themembers 26 and 29 to normal positions similar to that illustrated nFIGURE 2, the top ends of the springs being rigidly- :onnected to therespective terminal members 19 and 2.0 1nd the lower ends of the springsbeing clampingly-se- :ured on the top ends of the rods 27 and 30. Thesprings 58 and 31 thus serve as flexible supports for the members .26and 29 and also as means to develop a restoring torque 'or urging themembers 26 and 29 toward their normal :ositions when said members aredisplaced therefrom. Ihe spherical member 26 is sufficiently oflset fromthe :enter line of the pole piece 22 so that it tends toswing oward saidcenter line responsive to the energization of he solenoid 21, and hassutficient inertia to engage the ion-magnetic cylindrical block 29 withsubstantial im- )act as it swings to the right from the position thereof.hown in FIGURE 2. When the impact is delivered to .he block 29, theblock 29 responds thereto by also swingng to the right from its normalposition shown in FIG- JRE 2. The spring 31, however, acts upon block 29to 'eturn it to the left from its outwardly-swung position. Epring 28also acts in a similar manner to return the ipherical member 26 towardits normal position -when it ras been displaced either to the right orto the left of the Josition thereof shown in FIGURE 2.

Mounted on remaining portions of the main supporting Jlate 12 areadditional elements interconnected with the iOlGl'lOld 21, the sphericalmember 26, and the block 29 .0 form a driving circuit arranged to causethe spherical nember 26 and the cylinder block member 29 to inter-:ngage and disengage in a random manner. FIGURE llustrates the circuitryof the device 11, showing the de- 1168 connected to a typical load,namely, an incandescent amp 32. Designated at 33 is a silicon-controlledrectifier. lhe silicon-controlled rectifier 33 is mounted on the up- )erportion of the main supporting plate 12, as shown in FIGURE 2. The baseelectrode 34 of the silicon-controlled 'ectifier 33 is connected to afirst alternating currentupply wire 35 and the output electrode 36 ofthe rectiier is connected to one terminal of the incandescent lamp 2, asshown at 16. The remaining terminal of the in- :andescent lamp 32 isconnected to terminal 18 by a wire i7, the remaining line wire 38 beingconnected to said erminal 18. As shown in FIGURE 5, the first-mentioned.upply-line wire 35 is connected to the terminal 17 to vhich isconnected a conductor 39 leading to the base 34 If thesilicon-controlled rectifier 33, the terminals 15 and .4 being likewiseconnected to said wire 39. Thus, the line vires from the supply sourceof alternating current are onnected across the terminals 17 and 18 andthe load,

lamely, the incandescent lamp 32, is connected across the erminals 16and 18. The lead wires from the load 32 .re shown at 37 and 40.

The lead wire from the output electrode 36 of the ilicon-controlledrectifier 33 is shown at 41. Connected .cross the terminals 15 and 16,and thus, connected .cross wire 39 and 41 is a resistor R1, and alsocontected across wires 41 and 39 is the electromagnetic wind- 1g 21.Connected across terminals 20 and 16, namely,

between terminal 20 and conductor 41, as shown in FIG- URE 5, is aresistor R2, and connected between terminals 20 and 14 is anotherresistor R3. The cylindrical block member 29 is connected to thejunction terminal 20 through the rod 30 and the spring 31 as shown inFIG- URE 2. The spherical magnetic ball 26 is connected to the terminal19 through the rod 27 and the spring 28, as shown in FIGURE 2. Aradio-frequency filter-capacitor C1 is connected across the terminals 17and 18, serving as a shunt for radio-frequency energy so as tosubstantially eliminate radio-frequency interference from the device.

The gate electrode of the silicon-controlled rectifier 33 is connectedby a wire 42 to a terminal 19, and thus, is connected to the magneticspherical ball 26.

In operation, when the conductors 35 and 38 are connected to theterminals of the alternating currentpower source, current flows throughthe load 32 and also through the electromagnetic winding 21, generatinga magnetic field at the pole piece 22 which attracts the magnetic ball26 causing it to move rapidly toward the center line of the pole piece.In so doing, it collides at an oblique angle with the cylindrical block29, accelerating the block 29 into an orbital path and also causingalteration of the path of movement of the spherical ball 26. When ball26 engages block 29 the gate electrode of the silicon-controlledrectifier 33 is connected to the junction terminal 20 between resistorsR2 and R3 which applies gating voltage to the silicon-controlledrectifier, which turns on the silicon-controlled rectifier for a portionof a half-cycle of current. During this period, substantially all of thecurrent flow of the branch circuit between conductors 41 and 39 isthrough the siliconcontrolled rectifier. Consequently, the currentthrough resistor R1 and the electromagnetic winding 21 is reduced tonearly zero, causing the magnetic field at pole piece 22 to collapsesubstantially to zero. The rebound inertia of the bodies 26 and 29disengages them and moves them away from each other, and hence, removesthe control voltage from the gate electrode of the silicon-controlledrectifier, thus returning the silicon-controlled rectifier to anon-conductive state, which restores current flow through theelectromagnetic winding 21, restoring the magnetic field at the polepiece 22. Hence, the magnetic field again affects the path of movementof the spherical ball 26 which causes it to swing back and again collidewith the block 29. Repeated collisions of this type occur at differenttimes and at diflerent orbital positions of the members 26 and 29 andproducing changes in the elliptical orbits which shift their vectorscontinuously ver complete 360 cycles.

Due to the many dependent variables which are present in the system,namely, acceleration, inertia, contact resistance, velocity, andmagnetic orbital flight paths, associated with the magnetic ball 26,collisions constantly occur, correspondingly gating thesilicon-controlled rectifier 33 so as to cause a fluctuating magneticfield at the pole piece 22, which correspondingly acts on the magneticball 26, which, in turn, aflects the magnitude of its impact atcollision with the block 29, producing a random dynamic conditionwherein the silicon-controlled rectifier 33 is gated by a multiplicityof random collisions. This causes random conduction of thesilicon-controlled rectifier 33, producing a random low-resistance pathfor the current flowing to the incandescent lamp load 32. Thesevariations in current flow and voltage drop appear as random variationsin the light output from the lamp 32.

While it is quite difficult to analyze the action of the deviceabove-described, it is to be noted that the primary and secondary movingparts 26 and 29 are continually seeking a naturally steady state. Underthe influence of the fluctuating magnetic field, the variations of whichare determined by the frequency of the collisions between the members 26and 29, the members are directly and indirectly forced away from theirsteady-state positions,

The opposing forces between them being directed in accordance with theirproximity to their steady-state points. In other words, the further thebodies 26 and 29 are away from their steady-state positions, the lessthe average opposing force between them becomes; the closer to theirsteady-state positions, the greater the average opposing force betweenthem becomes. The members 26 and 29 are continually orbiting betweenthese two extremes. Their interaction results in a highly unstableelectromechanical condition which is reflected in the random gating ofthe silicon-controlled rectifier 33. The resulting power fluctuationsproduce an unsteady faltering light output from the lamp 32 creating theillusion of an op n flame. When the lamp 32 is employed with anappropriate lighting fixture, such as in a candelabra, an outdoor postlatern, a wall-mounted coach lamp, or a similar decorative fixture, theend etfect enhances to a very significant degree the charm and beautyfor which these fixtures were originally designed.

In low-power applications of the random-gate device, such as for use asa radio-frequency noise generator, namely, a white noise generator, thesilicon-controlled rectifier 33 may be omitted; in this case the members29 and 26 are connected directly across the electromagnetic winding 21and the resistors R2 and R3 are omitted. This modification isillustrated in FIGURE 6.

It will be noted that in the arrangement illustrated in FIGURES 1 to 5,a substantial current flows through the load 32 even when the members 29and 26 are separated, thus maintaining usable light output from the lamp32, even at the lowest illumination level of the lamp. It is to befurther noted that since the range of the power gating never appliesmore than approximately 90% of the rated voltage to the lamp, the lamplife is significantly extended. Also, since the lamp is neveropen-circuited completely, and is provided with a substantial amount ofcurrent even under its low-level condition, thermal shocks areminimized, providing another advantage With respect to extending thelife of the lamp and reducing the necessity for frequent lampreplacements. Also, because the fundamental excitation is from anonlinear complex mechanism which has an infinite number of degrees offreedom in a horizontal plane, the output to the lamp is truly random inform, containing a gentle waver rather than a relatively continuoussputtering effect.

While certain specific embodiments of an improved random current-gatingdevice have been disclosed in the foregoing description, it will beunderstood that various modifications within the spirit of the inventionmay occur to those skilled in the art. Therefore, it is intended that nolimitations be placed on the invention except as defined by the scope ofthe appended claims.

What is claimed is:

1. A random current-gating device comprising a pair of terminals adaptedto be connected in series with a load, an electromagnet, meansconnecting said electromagnet across said terminals, a first movableconductive member, said first conductive member being of substantialmass and being of magnetic material, means swingably supporting saidfirst conductive member to swing in any direction in the field of saidelectromagnet in a position to cause said first conductive member toswing responsive to energization of the electromagnet, a second movableconductive member of substantial mass and of non-magnetic material,means swingably-supporting said second conductive member to swing in anydirection in the path of movement of said first conductive member,whereby to be struck by the first conductive member and to reboundtherefrom responsive to such energization of the electromagnet, thecommon vertical plane of the conductive members in their rest positionsbeing oifset from the axis of the field of the electromagnet, andcircuit means to substantially short-circuit the electromagnetresponsive to the engagement of the two conductive members, whereby toestablish a shunt path across said terminals during said engagement.

2. The random current-gating device of claim 1, and wherein saidconductive members have side-by-side rest positions wherein they arespaced from each other.

3. The random current-gating device of claim 2, and wherein saidconductive members have substantially orbital paths of swingingmovement.

4. The random current-gating device of claim 3, and wherein said firstconductive member is substantially spherical in shape and said secondconductive member has a rounded impact surface facing the firstconductive member and being engageable thereby responsive to theenergization of the electromagnet.

5. The random current-gating device of claim 4, and a resistor connectedacross said electromagnet.

6. The random current-gating device of claim 4, and wherein said secondconductive member is substantially cylindrical in shape and isaxially-suspended.

7. The random current-gating device of claim 3, and wherein the means tosubstantially short-circuit the electromagnet comprises a normallynon-conducting siliconcontrolled rectifier connected across theelectromagnet and having a gating electrode, and circuit means toenergize said gating electrode to cause conduction of thesiliconcontrolled rectifier responsive to said engagement of theconductive members.

8. The random current-gating device of claim 7, and wherein the means toenergize said gating electrode comprises a pair of resistors connectedin series across the electromagnet, means connecting one of theconductive members to the junction of said pair of resistors, and meansconnecting the other conductive member to said gating electrode.

9. The random current-gating device of claim 8, and a source of current,a load device, and circuit means connecting said source of current inseries with said load device and said pair of terminals.

10. The random current-gating device of claim 9, and wherein said loaddevice comprises an incandescent lamp, and a radio-frequency-attenuatingfilter-capacitor connected across said source of current.

References Cited UNITED STATES PATENTS 3,304,482 2/1967 Ienks et al318330 3,145,323 8/1964 KlOtZ 315-209 3,047,773 7/ 1962 Morton 315-2052,960,627 11/1960 Hunt 315209 2,892,954 6/1959 Orlando 307-132 2,829,3154/1958 Hoekstra 315-208 2,762,951 9/1956 Journel 315-482 2,725,44111/1955 Burns 200 2,106,922 2/1938 Tascher 335--90 JOHN W. HUCKERT,Primary Examiner I. R. SHEWMAKER, Assistant Examiner US. Cl. X.R.

